题干

如图所示实验装置,弹簧测力计下面挂着条形铁块,螺线管中插有铁芯.现开关S拨在触点②位置且电流表示数为I.要使弹簧测力计的示数变大,下列操作方法能够实现的是(  )

A:将开关S拨到③位置,并通过调节仍使电流表示数为I

B:开关S位置不动,将铁芯从螺线管中取出

C:开关S位置不动将滑片P向b端滑动

D:将开关S拨到①位置,并通过调节仍使电流表示数为I

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答案(点此获取答案解析)

C,D

同类题3

阅读下面语段,完成下列小题。

退步与向前

王也

       唐朝布袋和尚《插秧诗》曰:“手把青秧插满田,低头便见水中天。心地清净方为道,退步原来是向前。”布袋和尚是从现实劳动中退步插秧的情境来阐述参禅的境界。

       社会在进步,人类在进步,每个人的成长也是在进步,当人们为了达到一个目标时,非千方百计克服困难不可。如果是非达到不可的,能停下来甚至退下来想想,就可以另辟蹊径寻找更加适合自己的道路,_______这就是人们常说的“退一步海阔天空”。如自唐朝始的科举,多少学子为此而孜孜不倦、刻苦学习熬成白头?因此出现了范进中举而精神失常的情况,更多的是像孔乙己一样的心不如愿,贫困潦倒。但是,也有不少学子知难而退,却取得非凡成就。

       作家刘诚龙做过一次有趣的调查,他把两份名单给人看,问是否熟悉这些人名。第一份名单是:傅以渐、王式丹、毕沅、林召堂、王云锦、刘子壮、陈沅、刘福姚、刘春霖。第二份名单是:李渔、顾炎武、金圣叹、黄宗羲、吴敬梓、蒲松龄、洪秀全、袁世凯。结果,被调查者多数对第一份名单中的人一无所知,而对第二份名单耳熟能详。谜底最后揭晓:第一份名单里的人,全是清朝的科举状元;第二份里的人,全是当时的落第举子!

      想当年,第一份名单上的人多么显赫啊!但由于在官场上的打磨,以致状元郎归于平庸,湮没无闻。而第二份名单中的人,名落孙山,与高官厚禄无缘。但是,他们很快调整心态,在逆境中奋起,有的成为思想家,有的成为文学家,有的成为农民领袖,有的成为一代枭雄,声名鹊起,载入史册。

       不少生活实践告诉我们,农人插秧,一步步倒退,退到最后,秧便插好了,看起来是退步,实则是向前。船舶前行,双桨却往后划动;箭拉得越往后,射出的距离就越远……

       不少青年人有着远大的理想,更有不少到处碰壁还执迷不悟。我们要鼓励勇往直前,也要劝告毫无进展的人及时认清方向转型,善于退步,才能找到更加适合自己的发展道路。电视剧《潜伏》中有一句台词:“有一种胜利叫做撤退。”退,有时是为了更好地进。

同类题4

阅读理解

    Having three cancer patients in the same household can turn a whole family upside down. Michelle Bruce, her husband, Jeremy, and their son, Holden, all had cancer. The family moved to Michelle's hometown of Franklin, Nebraska six years ago, so her parents could help.

    Doctors found Holden's brain tumor(肿瘤), when he was 12 years old. His family was living in a small town at the time, but there were related doctors in the state. Holden had two operations in Omaha clinic, both of which were tough.

    When Holden's cancer came back again in 2012, nothing could be done. But the family didn't give up. They reached out to Boston Children's Hospital, which has better equipment and doctors with more experience operating on kids. After looking at Holden's records, the doctor sent back her diagnosis: She was confident that she could remove the tumor.

    The family was beyond relieved, until they learned insurance wouldn't cover any of the operation's costs. The operation would cost $39,000 – more than the parents could afford. The family got desperate.

    In a town of just 1,000 people, however, word traveled fast. Within days, a local woman Michelle had never met in person called to say she was planning an event to raise money for Holden. Michelle was touched.

    The event was uplifting. Finally, the town raised $45,000 – enough to cover not just Holden's hospital bills, but for Michelle and Jeremy's trip to Boston with their son. “I just didn't know what to say,” said Michelle. “Nobody could really believe it.”

    Holden's operation went much more smoothly than the first two. He is cancer-free and now is attending Central Community College-Hastings on a full-ride scholarship.